Keyboard not working after update to 18.04

Installing xserver-xorg-input solved my problem !

Expanding on the above for the inexperienced, it is possible to turn on the on-screen keyboard (accessibility menu) as it is likely that external USB keyboards will also not work. After that perhaps the command

sudo apt-get install xserver-xorg-input-all

will do it. You need to shutdown and reboot each time (closing the lid usually just puts it to sleep).

At time of login press Ctrl+Alt+F3.
Then input your username and password.
After that, input the command

sudo apt-get install xserver-xorg-input-all

Then input

startx 

And your problem will be solved.

For anyone who still has this issue, in my case it's that somehow "Slow Keys" was turned on in the accessibility menu (little person icon in the upper-right corner of the login screen).

Was driving me crazy!